Why is a white cat able to prove that the world is as black as a crow ?

There is a saying called "the world is as black as a crow", let's not forget its extended meaning, just see it as a logic.

on inductive propositions. How, then, do you prove that this proposition is true? Obviously, according to the inductive method.

Unless we have caught all the ravens and looked at them, it is impossible to fully prove the truth of this proposition; And we can't guarantee that we've caught all the crows in the world.

However, we can still increase the reliability of this proposition, that is, increase its credibility. The easiest way to think of this is to look for crows in nature, and each time you find a black crow, the credibility of the proposition increases. However, we don't have to work so hard to find crows, because logically a white cat can prove that "the world is as black as a crow"!

We already know that statements that can be judged to be true or false are called propositions. If there are two propositions, and the condition and conclusion of one proposition are the conclusion and the negation of the condition of the other proposition, respectively, then the two propositions are "inverse negative propositions" to each other.

In logic, the original proposition and its inverse proposition are equivalent propositions, i.e., if the original proposition is true, then its inverse proposition is also true.

For example, the proposition "the world is as black as a crow", according to the definition, its inverse proposition is "everything that is not black is not a crow". These two propositions are a pair of equivalent propositions. In other words, if "the world is generally black as a crow" is true, then "everything that is not black is not a crow" is also true, and vice versa.

This means that if we want to prove that "the world is as black as crows" is true, then we can also achieve the same goal by proving that "everything that is not black is not a crow".

How to prove that "nothing that is not black is not a crow"? Obviously, if we meet a white cat, we will undoubtedly be able to increase the probability that this proposition is true, and at the same time, it will also increase the probability that the original proposition "the world is as black as a crow" is true.

Summary:Therefore, from a logical point of view, meeting a white cat can slightly increase the probability that the proposition "the world is as black as a crow" is true. Sounds interesting, right?

This is a one-sided statement, crows also have white, gray ones. It's just that the crows that people saw in the past were black, so there is such a saying. Of course, the word has now been given a new connotation.

Because the color of the white cat is very bright, if you put this white cat in a pile of black, it is very eye-catching, so it is very clear that you can see it.

Because this white cat is so pure, as long as the crows with dark colors are black, there is such a saying.